Therapeutic Intervention of the JAK/STAT Pathway for Neuroinflammation

描述（由申请人提供）：多发性硬化症（MS）的特征是中枢神经系统的局灶性炎症浸润，脱髓鞘病变和轴突损伤，导致神经功能障碍。先天免疫和适应性免疫系统细胞参与多发性硬化症的发病机制。多发性硬化症的另一个特征是产生激活免疫细胞的细胞因子，包括IFN-？、IL-6、GM-CSF、IL-12和IL-23。JAK/STAT通路是细胞因子用于信号传导的途径，对免疫反应的发生、调节和终止至关重要。在之前的资助期内，我们开发了一种实验性自身免疫性脑脊髓炎（EAE）模型，其中JAK/STAT通路在髓细胞中异常激活，具有Th1和Th17细胞分化的功能后果。该模型呈现为非典型EAE的非溶解形式。在这个JAK/STAT通路激活增加的非典型模型中，我们证明了AZD1480，一种JAK/STAT通路抑制剂，抑制疾病严重程度，阻止免疫细胞进入中枢神经系统，抑制Th1和Th17细胞的分化，降低STAT激活，并降低细胞因子/趋化因子的表达。此外，我们还在其他四种EAE模型（经典型、复发缓解型（RR）、Th1或Th17细胞过继性转移）中测试了AZD1480，并观察到惊人的临床疗效。另一种JAK/STAT抑制剂AZD5776也能抑制EAE的临床症状。我们假设JAK/STAT通路的不适当激活促进了先天和适应性免疫系统细胞的异常反应，导致MS中出现的神经炎症，并且该通路的治疗干预将改变MS的进展。在这篇修订的竞争性更新中，我们将在五种EAE模型中评估两种不同的JAK抑制剂AZD1480和AZD5776。AZD1480是JAK1和JAK2抑制剂，AZD5776抑制JAK1。在Aim 1中，将研究靶向JAK/STAT通路在活动性EAE（经典、非典型、RR）中的治疗效果。我们将评估1)哪些jak /STATs参与了疾病的发病机制；2)细胞类型（CD4+ t细胞、巨噬细胞、小胶质细胞、dc）激活JAK/STAT通路是有害的；3) JAK抑制剂治疗效果的分子基础。在Aim 2中，将测试JAK/STAT通路在调节Th1和Th17细胞致病潜能中的作用。Th1和Th17细胞都具有诱导中枢神经系统自身免疫的能力，但具有不同的致病机制。我们的初步结果表明AZD1480对th1诱导和th17诱导的EAE均有抑制作用。我们将评估在mog免疫的背景下，AZD1480/AZD5776在体内治疗如何调节Th1和Th17细胞的发育程序和/或致病性。在Aim 3中，我们将研究JAK抑制剂AZD1480和AZD5776调节免疫细胞功能的机制。用JAK抑制剂处理的幼年小鼠获得的巨噬细胞和dc将被评估其抗原呈递能力、分化为促炎或抗炎表型以及潜在的神经保护特性。来自JAK抑制剂处理小鼠的CD4+ t细胞将被检查其随后分化为致病性和/或保护性t细胞亚群的能力。这些研究将为最终测试人类MS中JAK/STAT通路抑制剂奠定必要的临床前基础。

DESCRIPTION (provided by applicant): Multiple Sclerosis (MS) is characterized by focal inflammatory infiltrates of the CNS, demyelinating lesions and axonal damage, leading to neurologic dysfunction. Cells of the innate and adaptive immune system are involved in MS pathogenesis. MS is also characterized by production of cytokines that activate immune cells, including IFN-?, IL-6, GM-CSF, IL-12 and IL-23. The JAK/STAT pathway is used by cytokines for signaling, and is critical for the development, regulation and termination of immune responses. In the previous funding period, we developed a model of Experimental Autoimmune Encephalomyelitis (EAE) in which the JAK/STAT pathway is aberrantly activated in myeloid cells, with functional consequences for Th1 and Th17 cell differentiation. This model presents as a non-resolving form of atypical EAE. In this atypical model with heightened activation of the JAK/STAT pathway, we demonstrate that AZD1480, an inhibitor of the JAK/STAT pathway, suppresses disease severity, prevents entry of immune cells into the CNS, suppresses differentiation of Th1 and Th17 cells, decreases STAT activation, and reduces expression of cytokines/chemokines. Furthermore, we have tested AZD1480 in four other EAE models (Classical, Relapsing-Remitting (RR), Adoptive Transfer of Th1 or Th17 cells) and observed striking clinical efficacy. Another JAK/STAT inhibitor, AZD5776, also inhibits EAE clinical symptoms. We hypothesize that inappropriate activation of the JAK/STAT pathway promotes aberrant responses of cells of the innate and adaptive immune systems, leading to the neuroinflammation seen in MS, and that therapeutic intervention of this pathway will alter the progression of MS. In this revised, competing renewal, we will evaluate two distinct JAK inhibitors, AZD1480 and AZD5776, in five EAE models. AZD1480 is a JAK1 and JAK2 inhibitor, and AZD5776 inhibits JAK1. In Aim 1, the therapeutic efficacy of targeting the JAK/STAT pathway in active EAE (classical, atypical, RR) will be examined. We will evaluate 1) which JAKs/STATs are involved in disease pathogenesis; 2) in which cell type(s) (CD4+ T-cells, macrophages, microglia, DCs) activation of the JAK/STAT pathway is detrimental; and 3) the molecular basis for the therapeutic benefit of the JAK inhibitors. In Aim 2, the role of the JAK/STAT pathway in regulating the pathogenic potential of Th1 and Th17 cells will be tested. Both Th1 and Th17 cells have the capacity to induce CNS autoimmunity, but have differential pathogenic mechanisms. Our preliminary results indicate that AZD1480 is effective in inhibiting both Th1-induced and Th17-induced EAE. We will assess how in vivo treatment with AZD1480/AZD5776 in the context of MOG-immunization regulates the developmental program and/or pathogenicity of Th1 and Th17 cells. In Aim 3, the mechanism by which the JAK inhibitors AZD1480 and AZD5776 regulate immune cell function will be examined. Macrophages and DCs obtained from naive mice treated with JAK inhibitors will be evaluated for their antigen presentation capability, polarization into proinflammatory or anti-inflammatory phenotypes, and potential neuroprotective properties. CD4+ T-cells derived from JAK inhibitor treated mice will be examined for their subsequent ability to differentiate into pathogenic and/or protective T-cell subsets. These studies will establish the pre-clinical foundation necessary to ultimately test inhibitors of the JAK/STAT pathway in human MS.